PHOTOSYNTHESIS AND GROWTH OF POPLAR TREES 267 



16 18 



Bg 000000000000 



i-o- 



e 0-6 



O 



I 



02- 



Transpiration 



10 



-T 



12 



14 



16 



IB 



W^ 



\7 south side of the crown 



^ crown interior 



▼ north side of the crown 



Fig. 10. Assimilation and transpiration ofQuercus ccrris in different regions of the crown, 

 24/8/59; outpost of tiie forest steppe. S = total radiation, C3.l./cm?/imn; T=air temp, 

 °C; rF= relative humidity of air, percent; W=wind velocity, m/sec; Bg= cloud 

 cover (Bedeckungsgrad) . 



